The copied drawing sheets are added and highlighted at the end of the sheet list. When a sheet is copied, its name is created by the addition of -copy(n) at the end of the original sheet name.
For example, if you create one copy of a sheet called Plumbing, the copied sheet is called Plumbing-Copy(1).
Each time you copy the same sheet, the n is incremented by 1. By creating copies of a sheet, you can have different page setups and other settings for the same sheet.